How to remove background colors in antialiasing pixels in Eevee?
Change the world background to a black color and it should look fine.

In this example I am using a world enviroment but wanted a color/alpha to appear for the camera/render.

At first the render came out with a light blue border over objects, and as I changed the "world bg" to black with the light path node, the render came out fine, without borders.

I hope this can be understood easily, im at work and typing this without thinking it too much